WP breaking PHP tags

Hi, this is my first post and I have a tiny and irritant problem.

In my blog I will (in the future, because it’s not ready yet) post PHP codes and the PHP tags (<?php) are being “broken” by WordPress (I guess) or one of various plugins.

The way of “break” is, after I publish a post, <?php is turned into <? php,with a extra space added inside them.

I have a screenshot of all my plugins here but I don’t know the problematic plugin (if a plugin is the problem)

So, I’m sory for the English grammar and thank you in advance.